1. Technical Field
The present invention relates to a computer system for controlling a screen display of a monitor in a power management mode, and more particularly, relates to a computer system for controlling a screen display of a monitor in a power management mode according to input of a password for protecting confidential information from unauthorized users when the computer system is reawakened from a graphic off mode.
2. Related Art
Contemporary computer systems generally consist of a main unit (which may have built-in storage devices such as floppy disks, hard disks and CD-ROM), a keyboard and a monitor. The main unit may be connected to a cathode-ray tube (CRT) monitor and other peripheral devices. In normal usage, it is common for the monitor and other peripherals to be turned on and to remain on for as long as the computer is running, even though the peripherals are actually used only a small percentage of the time. A typical color video monitor, for example, may consume as such as 50 to 80 percent of the total electrical energy consumed by a personal computer (PC). If the monitor consumes valuable energy only to remain idle, not only the valuable energy resources will be wasted but the life of the monitor will decrease rapidly. Obviously, power can be conserved if the user turns the computer system off or in a standby mode each time the computer system is no longer in use for a prolonged period. This requirement is, however, impractical. Therefore, system should be designed to automatically conserve valuable energy resources when the computer system is not in use.
In principle, automatically saving energy by turning off the computer system is fairly easy. Computer systems are invariably designed so that if there is no activity from the keyboard or from other external inputs during a specified time, the computer systems are turned off or placed in a standby mode to save energy. Only minimal logic is kept active to detect when the keyboard or other external inputs are becoming active again so as to turn the computer system back on. Conventional power saving features for typical personal computers having monitors as separate items are disclosed, for example, in U.S. Pat. No. 5,163,124 for Method And Apparatus For Controlling Power To Device In A Computer System issued to Yabe et al., U.S. Pat. No. 5,218,704 for Real Time Power Conservation For Portable Computers issued to Watts, Jr., U.S. Pat. No. 5,375,245 for Apparatus For Automatically Reducing The Power Consumption Of A CRT Computer Monitor issued to Solhjell et al., U.S. Pat. No. 5,389,952 for Low-Power-Consumption Monitor Standby System issued to Kikinis, U.S. Pat. No. 5,408,668 for Method And Apparatus For Controlling The Provision Of Power To Computer Peripherals issued to Tornai, U.S. Pat. No. 5,410,713 for Power Management System For A Computer issued to White, and recently U.S. Pat. No. 5,483,464 for Power Saving Apparatus For Use In Peripheral Equipment Of A Computer issued to Song and assigned to the same assignee of the present invention. Usually, the monitor is shut down during the period of inactivity with the exception of a small amount of power necessary to detect when the computer system becomes active again so as to resume operation of the monitor. Generally, when the monitor is powered normally, the display of data image is blanked during the period of inactivity and re-displayed when the computer system becomes active, i.e., when an input device such as a keyboard is operated. During this type of blanking, however, the monitor continues to consume normal power.
Display power management standards have been set to save power consumption by controlling monitor power with respect to the operational status of the computer system. In the power management mode, power supply is managed according to the operational status of the computer system. The mode status of the power management is classified into power-on, standby, suspend and power-off. First, when the computer system is first turned on, power is continuously supplied to each device of the computer system in a power-on mode. After a period of inactivity, the computer system is switched to a standby mode to reduce power consumption by lowering the operation frequency of a central processing unit (CPU), turning off operation of a monitor, and turning off operation of a hard disk drive (HDD). The computer system may also be temporarily suspended in a suspend mode when there is a sudden power failure or when the computer system is not accessed for a predetermined time period. Lastly, the computer system may be turned off completely in a power-off mode.
During the standby mode, the computer system can be automatically awakened and the mode of the computer system is converted back into the full power-on mode without checking a password when there is an external input such as input from a keyboard, a mouse, and an infrared port, and activity from a hard disk drive (HDD), a floppy disk drive (FDD), a fax/modem card, and a network card. During the suspend mode, the computer system provides a visual display of identification information such as "enter password" on a monitor when the power switch is turned on if the password is set at the time of the computer setup, and the mode of the computer system is converted into the full power-on mode after checking that the input password is correct. The mode of the computer system is converted into the full power-on mode without checking the password if the password is not set at the time of the computer setup.
The mode of the computer system is converted into the full power-on mode after checking the password if the password is set at the time of the computer setup when the power switch is turned on, and the mode of the computer system is converted back into the full power-on mode without checking the password if the password is not set at the time of the computer setup. However, typical computer system, as I have observed, has a disadvantage in that information can not be kept confidential from unauthorized users since the password is not needed, before the computer system is converted into a suspend mode, to convert the computer system back into a full power-on mode.